package com.tawl.common.filter;

import com.tawl.common.enums.HttpMethod;
import com.tawl.common.utils.StringUtils;

import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * 防止XSS攻击的过滤器
 *
 * @author tongai
 */
public class XssFilter implements Filter {
  /**
   * 排除链接
   */
  public List<String> excludes = new ArrayList<>();

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    String tempExcludes = filterConfig.getInitParameter("excludes");
    if (StringUtils.isNotEmpty(tempExcludes)) {
      String[] urls = tempExcludes.split(",");
      excludes.addAll(Arrays.asList(urls));
    }
  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
          throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse resp = (HttpServletResponse) response;
    if (handleExcludeURL(req, resp)) {
      chain.doFilter(request, response);
      return;
    }
    XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request);
    chain.doFilter(xssRequest, response);
  }

  private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response) {
    String url = request.getServletPath();
    String method = request.getMethod();
    // GET DELETE 不过滤
    if (method == null || HttpMethod.GET.matches(method) || HttpMethod.DELETE.matches(method)) {
      return true;
    }
    return StringUtils.matches(url, excludes);
  }

  @Override
  public void destroy() {

  }
}